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Staying Grounded: Research Helps Power Plants Reuse Coal Combustion Products
For half a century, many surface coal mines in Ohio have remained abandoned and unusable.
Now an Ohio State University researcher is working with the state’s power plant industry to reclaim the lands by safely using byproducts, called coal combustion products (CCPs), of the coal burned at the plants.
Every ton of high-sulfur coal burned in Ohio produces about 0.8 ton of coal combustion products, says Tarunjit Singh Butalia, a research associate professor of civil, environmental and geodetic engineering, who has been studying ways to beneficially use those products for two decades.
Ohio power plants generate approximately 10 to 12 million tons of CCPs annually. Although about 35 percent gets used in various application technologies, the remaining 65 percent typically is destined for disposal in permitted landfills or ponds designed to retain these byproducts.
“By scrubbing the coal, we are swapping an air pollution problem with a solid waste problem,” Butalia says. “The smarter way would be to use that solid waste to solve other problems, such as those related to reclamation of abandoned mined lands in the vicinity of where the solid waste is being generated.”
Indeed, Butalia and his research colleagues have discovered ways to use coal combustion products as low-cost substitutes for conventional raw materials in highway and related civil engineering applications as well as manufacturing industry and agricultural applications. They also determined that stabilized products resulting from the sulfur dioxide scrubbing processes at coal-fired power plants could be used in the reclamation of abandoned and active Ohio coal mine sites.
Among Butalia’s successes is a partnership with American Electric Power and local, state and other industry partners to use the coal combustion products as a fill to return surface coal mine land to a more environmentally sustainable state.
“These reclamation projects can reduce the environmental risks abandoned mined lands cause,” Butalia says, “such as disrupted flow of surface water, acid mine drainage, dangerous land conditions and degraded wildlife habitats.”
To implement the findings, Butalia's team, with funding from the Ohio Development Services Agency, collaborated with AEP to divert from landfills approximately 1.7 million tons of coal combustion byproducts over approximately three years and use them to rebuild abandoned mine land surrounding AEP’s Conesville Power Plant in Coshocton County, Ohio. An additional planned site has the potential to use about 4 million tons of byproducts over the next several years.
As part of his summer state tour, Ohio State University Michael V. Drake, M.D., visited the plant to learn about the research. “AEP’s commitment to these projects is very, very significant,” said Butalia.
For its part, AEP also touts the collaboration aspect.
“The coordination we’ve had between the government agencies, Ohio State and the Conesville plant employees has been outstanding,” said John Massey Norton, senior hydrogeologist with AEP, who has worked on the projects with Butalia. “These projects would not have been possible without that cooperation.”
The project, which was completed in 2016, eliminated over 2,400 linear feet of highwall — the tallest point of an area of mined land — and reclaimed 22 acres of abandoned mined lands. AEP planted native grasses and more than 9,000 trees at the sites, where natural reforestation also is occurring. Drainage and erosion complications were eliminated with careful planning and collaboration with the Ohio Department of Natural Resources.
Massey Norton noted that vernal pools are now forming at the sites, enabling ecology to return to its natural state.
“In addition, the silt deposit at the sites retains rainfall, allowing it to dissipate at a steady flow rate into the streams,” he said. “If you increase the base flow of any stream, you’re going to improve the stream ecology.”
In addition to the proven research and the strong industry and state collaborations, the CCP project results in benefits for and from students.
“Projects such as these are living laboratories that provide unique opportunities for research and teaching which are rarely available within the boundaries of a university campus,” Butalia said. “In last two decades, we have successfully graduated five doctoral students and 15 master’s students and trained over 50 undergraduate students.”
Now, the CCP project has progressed from the research phase overseen by Ohio State researchers to a potentially commercially viable process implemented and managed by AEP at no cost to the State of Ohio. AEP is reclaiming two more sites at Conesville to eliminate approximately 5,000 linear feet of highwall and reclaim over 100 acres of abandoned mine land. AEP estimates that these mine reclamation projects near the Conesville Power Plant could provide sufficient capacity for up to 10 years of CCP production, so the company postponed the construction of a second landfill for that plant.
Butalia and his colleagues are working on similar projects at other coal-fired power plants in Ohio.
State and national reclamation groups have begun to recognize the collaborative efforts of the Ohio State researchers.
“Your example shows what can be done when all parties sincerely work together to improve the technologies necessary for human civilization and protection of the environment,” says Kimery Vories, president of the American Society for Mining and Reclamation, who recently attended a tour of the project site with the Ohio Mineland Partnership.
From its start, a strong coalition including the State of Ohio, Ohio State, Ohio utilities, ash marketers, private businesses and trade organizations has funded the research. Reuse of the coal combustion products provides a low-cost raw construction material, extends the life of landfills and lessens the need for new ones, and helps keep energy production costs in check. The reclamation of these large tracts of land reduces dangerous highwalls and environmental impacts, benefitting local communities, hikers, and ATV enthusiasts alike.
by Joan Wall, Office of Energy and Environment